1. Field of the Invention
The present invention relates to an exposing apparatus for a fabricating process of a flat panel display device and more particularly to an exposing apparatus where damage on a beam edge cutter is being capable of being prevented.
2. Discussion of the Related Art
As the society has entered in earnest upon an information age, flat panel display devices, which have excellent capabilities of a thin profile, light weight and low power consumption, and so on, are introduced and used instead of a cathode ray tube (CRT). For example, the flat panel display devices include an LCD device, a plasma display panel (PDP) device, an electroluminescent display (EL) device and a field emission display (FED) device. These flat panel display device includes a flat panel display panel, which includes a pair of substrates and a material layer including a fluorescent material or a phosphorescent material, as an essential member.
Recently, an active matrix type flat panel display device, where pixels are arranged in a matrix shape and a thin film transistor as a switching element is independently controlled, is widely used.
For example, the LED devices, which are widely used for notebook computers, monitors, TV, and so on, because of their high contrast ratio and characteristics adequate to display moving images, includes a liquid crystal panel having a first substrate, a second substrate and a liquid crystal layer. The first and second substrates face each other, and the liquid crystal layer is interposed therebetween. On the first substrate, gate and data lines cross each other to define a pixel region. A thin film transistor (TFT) at a crossing portion of the gate and data lines is connected to a pixel electrode in the pixel region. The first substrate may be referred to as an array substrate. On the second substrate, a black matrix having a lattice shape, a color filter layer and a common electrode are formed. The black matrix shields the gate line, the data line and the TFT, and the color filter layer includes red, green and blue color filter patterns. The common electrode generates an electric field with the pixel electrode to drive the liquid crystal layer. An arrangement of the liquid crystal molecules in the liquid crystal layer is changed by an electric field induced in the liquid crystal panel to control light transmissivity.
Generally, an additional light source is required because the LCD panel is a non-emissive-type display device. Accordingly, a backlight unit is disposed under the LCD panel. The LCD device displays images using light produced by the backlight unit and supplied to the LCD panel.
A fabricating process of the flat panel display devices includes a depositing process for forming a thin film on a substrate, a photolithography process for exposing a portion of the thin film and a patterning process for removing the exposed portion of the thin film.
The photolithography process includes a coating step for forming a photoresist (PR) material layer on the thin film, an exposing step for exposing a portion of the PR material layer using a mask including a desired pattern and a developing step for removing an exposed portion or a non-exposed portion of the PR material layer using a developing solution. A PR pattern having a desired pattern is obtained by the photolithography. As the LCD device having a large size and a high resolution is required, a fine process is required in the exposing step.
FIG. 1 is a perspective view of the related art exposing apparatus. In FIG. 1, the exposing apparatus includes a light source 10 for emitting light, for example, ultraviolet ray or X-ray, a mask 20 including a desired pattern, a stage 30, where a substrate 2 is disposed, and a beam edge cutter 40 for providing uniform light onto the mask 20. The beam edge cutter 40 and the mask 20 are positioned between the light source 10 and the stage 30, and the beam edge cutter 40 is positioned between the light source 10 and the mask 20. The beam edge cutter 40 includes at least one lens (not shown) and a reflex mirror (not shown). On the substrate 2, a thin film 4 and a PR material layer 6 are stacked.
The mask 20 and the beam edge cutter 40 are disposed over the substrate 2 to be parallel such that light emitted from the light source 10 is irradiated onto the PR material layer 6 through the mask 20 and the beam edge cutter 40. As a result, if the PR material is a positive type, an irradiated portion of the PR material layer 6 is chemically changed. In the developing step, the chemically changed portion of the PR material layer 6 is removed using a developing solution such that a PR pattern having the same shape as a pattern of the mask 20 is formed on the thin film 2. Then, the thin film 2 is etched using the PR pattern as an etching mask in the patterning step.
In the above exposing apparatus, a PR material fume is evaporated from the PR material layer 6 during the exposing step. The PR material fume is deposited onto the lens and reflex mirror of the beam edge cutter 40. As a result, transmissivity of the lens and the mirror is degraded such that there are defects on the thin film and a processing efficiency is decreased.